The Red Sox activated catcher Jarrod Saltalamacchia and infielder/outfielder Eric Patterson from the 15-day disabled list and recalled left-handed reliever Dustin Richardson from Triple-A Pawtucket on Wednesday, the first day that clubs could expand their rosters.

Saltalamacchia had been on the DL since Aug. 19 due to a lower right leg infection. He was hospitalized for a couple of days while receiving IV fluids and antibiotics.

In four rehab games with the PawSox, the 25-year-old Saltalamacchia was 5-for-15 (.333) with a homer, two doubles and four RBIs.

Saltalamacchia is 2-for-6 (.333) with a pair of doubles in three games with the Red Sox since being acquired in a trade with Texas on July 31.

Patterson returned from Boston's 10-game road trip last month with a neck strain and was placed on the DL on Aug. 17. In four games with Pawtucket he went 4-for-17 (.235) with two doubles, a triple and three stolen bases while playing second base, center field and serving as the designated hitter.

The 27-year-old Patterson, acquired in a trade with Oakland on June 26, is batting .254 (17-for-67) with a pair of homers and six RBIs in 29 games with the Red Sox.

Richardson is with the team for the third time this season. The 26-year-old has a 2.61 ERA in 19 relief appearances with the big club. In 32 games with the PawSox he went 3-0 with two saves and a 2.66 mark.

Boston's active major league roster is at 28 players. The 40-man roster remains at 38. More minor leaguers may join the Red Sox in the coming days. Michael Bowden, who was optioned to Pawtucket on Saturday, needs another week before he is eligible to be brought back up. Outfielder Josh Reddick will likely rejoin the team once the PawSox' season ends Monday.